Sulfur-containing compounds are typically associated with a noxious odor. There are many situations in which this odor is beneficial. For example, small amounts of sulfur-containing compounds, for example, ethyl or methyl mercaptan, are added to liquid propane gas (LPG) and natural gas. LPG and natural gas themselves do not have an associated odor, and the presence of the methyl mercaptan allows one to detect the presence of the gases.
There are also many situations in which the sulfur-containing compounds are not beneficial. For example, hydrogen sulfide, which has a strong odor, is more toxic than hydrogen cyanide. Mercaptans and related compounds, such as thiolacetic acid, are extremely unpleasant to work with due to the associated noxious odor.
Hydrogen sulfide is known to react with and corrode copper metal and also numerous copper alloys via the formation of copper sulfide. This knowledge has been exploited commercially in industrial processes to scrub toxic hydrogen sulfide from off gases in large reactors.
For example, U.S. Pat. No. 5,700,438 to Miller discloses a process for removing hydrogen sulfide and mercaptans from gas streams. The process involves contacting gas streams with aqueous solutions of copper ammines, in which copper exists in the zero oxidation state, to form copper sulfide. The precipitation of copper sulfide frees up the amine used to form the copper ammine and allows it to react with additional copper to keep the concentration of the copper ammine relatively constant.
U.S. Pat. No. 5,741,415 to Mazgarov et al. discloses a process for the demercaptanization of petroleum distillates. The process involves oxidizing the mercaptans present in the distillates by contacting them with oxygen at elevated temperatures in the presence of a water-soluble copper ion. The copper ion is present on a fibrous carbonaceous material, such as a fabric, felt, rope or twisted strand.
U.S. Pat. No. 4,435,371 to Frech and Tazuma discloses a process for removing hydrogen sulfide, sulfides and mercaptans from a gas stream by contacting the gas stream with copper oxide, introducing ammonia onto the metal oxide, and then introducing hydrogen peroxide onto the metal oxide.
U.S. Pat. No. 5,457,234 to Shaw discloses a method for reducing the metal corrosiveness of an organic polysulfide by contacting the polysulfide with copper at an elevated temperature.
U.S. Pat. No. 4,701,303 to Nevers discloses a process for preventing a mercaptan from reacting with a metal container. The Nevers process involves pre-treating the container with benzotriazole, tolyl triazole, mercaptobenzothiazole, benzothiazyl disulfide or mixtures thereof. Nevers specifically teaches that it is beneficial to avoid having the mercaptan be deodorized for certain applications, namely, when the odor is essential for purposes of alerting one to potential leakage of liquid propane gas (LPG) or natural gas.
None of the foregoing references describe a solution for the problems of removing the noxious odors associated with sulfur-containing compounds present in storage or shipment containers including such compounds.
It would be advantageous to provide a container for transporting or storing sulfur-containing compounds that minimizes the presence of sulfur-containing compounds in the headspace of the container, such that those individuals opening the container would not be exposed to large amounts of noxious fumes. The present invention provides such a container.